SuperHouse shows us how to control various items around your house using your arduino microcontroller as the brain. This system uses an etherten arduino to allow it to be controlled from the internet. Some stacked relay modules that talk via I2C are used to control external devices. Once mounted in the custom case the module looks great. Sample code is provided that allows the system to work as a simple webserver that has a button interface to allow you to turn the relays on and off via the web.
“This episode shows the construction sequence of a controller that combines an Arduino-compatible board, Power-over-Ethernet, and relay driver shields to create a self-contained controller that can serve up its own web interface so you can click buttons in your browser to turn devices on and off.”